316i tappetty tap tap and hesitant

Tue Jan 09, 2007 11:46 pm

Just picked this up cheap. Driving at say 60 it can either run fine, or be very hesitant as if holding back, then go back to normal. Plus the tappets or cam sounds very tinny. The car has done about 180000 miles on a H reg.

It did back fire once on the M25. wasnt sure if exhaust fell off at first!

Any Ideas?

Wed Jan 10, 2007 9:47 am

Tappet noise is faulty hydraulic tappets. Relatively harmless, so live with it, or expensive repair, although experimenting with oil grades can sometimes help. Running one of mine on diesel oil for a few months improved one of mine (once I'd changed the diesel oil for the correct stuff).
First thing for the poor running is to check the big rubber hose from the air filter to the throttle body for splits.

Wed Jan 10, 2007 10:57 am

Brianmoooore wrote:Tappet noise is faulty hydraulic tappets. Relatively harmless, so live with it, or expensive repair, although experimenting with oil grades can sometimes help. Running one of mine on diesel oil for a few months improved one of mine (once I'd changed the diesel oil for the correct stuff).
First thing for the poor running is to check the big rubber hose from the air filter to the throttle body for splits.

how does that work?

Wed Jan 10, 2007 11:05 am

The diesel oil bit, I pressume you mean?
Oil made for diesel engines contains more detergents to keep the filthy, cancer causing machines clean inside.
This helps clean sludge and residues from the hydraulic tappets in a M40 and may improve them.

Wed Jan 10, 2007 11:41 am

oh i see, bloody hell i am impresed with you you seem to know every thing about e30s. keep up the good work

just a little test for you ,without looking, what size socket do you need to take the hub nut off a 320? as i dont think i have one that big and may have to purchase

Wed Jan 10, 2007 12:24 pm

Front is 36mm, IIRC, and has to be thin walled or ground down.
Back - don't get involved - change the whole rear beam.

Wed Jan 10, 2007 12:37 pm

Wed Jan 10, 2007 2:52 pm

"Oil made for diesel engines contains more detergents to keep the filthy, cancer causing machines clean inside."

Just out of interest I've got the usual massive tappety noise my my M40 - would using engine flush gunk help quieten them down or would it be a bad idea? I'm currently using Magnatec oil as well to try shut it up, but have since heard that the "magnetic oil" thing is a pack of lies - would I be better off using a decent full or semi synthetic?

So many questions - cheers....

Wed Jan 10, 2007 3:30 pm

Depends whether they are tapping because of excess wear or because of gunge.
Flushing the engine will help one and make the other worse.
Do you feel lucky?

Wed Jan 10, 2007 7:21 pm

If things are that bad then how much is another head inc cams etc fitted?

Wed Jan 10, 2007 7:36 pm

geeza wrote:If things are that bad then how much is another head inc cams etc fitted?

M40 engines are valued at close to Ã‚£0, so your best plan would be to find a good one for sale that you can hear running and change the whole engine and gearbox.
Much easier and cheaper than changing the head.
Most M40 engines will knock a little when cold, and possibly if left to idle when hot, but it's not really a problem if you can live with the noise.

Wed Jan 10, 2007 11:40 pm

Ta. As Im a complete numpty here ...is the 318i the same engine with a bigger bore?

Wed Jan 10, 2007 11:56 pm

316i and 318i E30s from about 87-88 onwards use the M40 engine. Both have the same bore, but the 1.8 has a longer stroke.
Far better engine is the M42 1.8 engine, as fitted to the 318iS and early E36 1.8s. This is the M40 engine revised to solve all its problems and fitted with a 16 valve twin cam head. Unfortunately they also introduced a fresh problem. in the form of the infamous profile gasket.
If you'd asked me a week ago, I'd have said these have all been sorted now, but we appear to have had two cases of failure on the zone in the last week or so.

Thu Jan 11, 2007 12:32 am

ha ha! typical! As a guestimate how much do these go for? As a complete transfer with all parts fitted?

Thu Jan 11, 2007 12:52 am

A straight swap of a M40 engine and box in an E30 is just a few hours work. Swapping for the M42 will take a bit, but not a lot, longer if you (and your insurance company) are happy with the inferior suspension and brakes of the i over the iS.

Thu Jan 11, 2007 1:05 am

hmm so putting in say the 318 is easy?

Thu Jan 11, 2007 9:17 am

Dead easy; plenty of room under a four pot bonnet.
Remove bonnet, radiator and gear lever. Undo exhaust and propshaft. Remove plugs from ECU and big socket by the fusebox, a couple of wires from battery, reverse light switch and earth strap. Undo a few pipes and a few nuts and lift.

Thu Jan 11, 2007 12:39 pm

hmm I think I'll still need a hand.

Ps have now sussed out that when cold the revs rise up and down. Still does it a little once warm

Thu Jan 11, 2007 1:28 pm

Brianmoooore wrote:316i and 318i E30s from about 87-88 onwards use the M40 engine. Both have the same bore, but the 1.8 has a longer stroke.
Far better engine is the M42 1.8 engine, as fitted to the 318iS and early E36 1.8s. This is the M40 engine revised to solve all its problems and fitted with a 16 valve twin cam head. Unfortunately they also introduced a fresh problem. in the form of the infamous profile gasket.
If you'd asked me a week ago, I'd have said these have all been sorted now, but we appear to have had two cases of failure on the zone in the last week or so.

dont mean to hijack but - Is this profile gasket the same as the Head Gasket? - ive started to look for another 318iS now and would appreciate some extra pointers.....

Thu Jan 11, 2007 1:37 pm

Spadge has a 318iS engine and box he is looking to move on BTW....

might be worth PMing him if you are looking to do a conversion....

Thu Jan 11, 2007 1:49 pm

robsy wrote:
Brianmoooore wrote:316i and 318i E30s from about 87-88 onwards use the M40 engine. Both have the same bore, but the 1.8 has a longer stroke.
Far better engine is the M42 1.8 engine, as fitted to the 318iS and early E36 1.8s. This is the M40 engine revised to solve all its problems and fitted with a 16 valve twin cam head. Unfortunately they also introduced a fresh problem. in the form of the infamous profile gasket.
If you'd asked me a week ago, I'd have said these have all been sorted now, but we appear to have had two cases of failure on the zone in the last week or so.
dont mean to hijack but - Is this profile gasket the same as the Head Gasket? - ive started to look for another 318iS now and would appreciate some extra pointers.....

The head gasket is exactly that, but the profile gasket lies between the front of head and the front timing cover. Keeps the water/coolant where it should be and the oil where that should be too. If the profile gasket has gone or is going look for traces of coolant staining below the exhaust manifold at cylinder 1.

Thu Jan 11, 2007 9:07 pm

robsy wrote: dont mean to hijack but - Is this profile gasket the same as the Head Gasket?

No, but you have to remove the head to change the profile gasket.
M40 had a timing belt, and the M42 has a chain. The profile gasket fits between the block and head at the front, accommodating the changes made for the chain.
The material chosen for this extra gasket proved to be not up to the job, and most failed in the 40,000 -80,000 mile range.
The new gasket is of a better material, so the failure should only occur once.